This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In collaboration with Dr. Paul Smith of Cardiff University, we will characterize the emission spectra of a new class of DNA binding dyes that are rapidly cell permeable and excite in the far red. The Cardiff group has characterized these dyes with a combination of conventional flow measurements, fluorescence spectroscopy of bulk samples and live cell spectral imaging. We will use stained cell lines to characterize the performance of the spectral instrument in the NIR region as compared to the other measurements. We will also use the improved PS cytometer to investigate changes in lifetime of these dyes upon DNA binding, potentially enabling separation of bound and unbound flurorophore in situ.